N54 vs N55 and 6sp vs 8sp

apollner · 10-13-2011, 08:27 AM

My lease is wrapping up on my 2009 X6 35i. I really have enjoyed the car so much, I've ordered another one! The current models now use the N55 engine and 8 speed transmission vs. my car's N54 engine and 6 speed.

Does anyone have any feedback from back-to-back comparisons on how these two changes affect the X6?

zerrantoss · 10-13-2011, 12:16 PM

I haven't personally driven a N54 X6, but have heard comments about it.
A lot of people are saying 8 spd is a lot smoother than 6 spd - should be true, given that you have 2 more gears..

However, I am not liking the sound of my N55 exhaust (with the right side opened with golf-tee mod, or with performance exhaust installed, etc). It sounds a bit "broken" to me...especially after a cold start. I am not sure if anyone else feel the same way.

AndreyATC · 10-13-2011, 12:54 PM

Besides smothiness, 8-speed equipped car is quicker and has better MPG than 6-speed variant
8AT might be even lighter in weight than 6AT, but i could be wrong

OTK_KART · 10-14-2011, 02:32 PM

Quote:

Originally Posted by zerrantoss

IHowever, I am not liking the sound of my N55 exhaust (with the right side opened with golf-tee mod, or with performance exhaust installed, etc). It sounds a bit "broken" to me...especially after a cold start. I am not sure if anyone else feel the same way.

I am the opposite. I have the 50i tip and I love the sound.

chocobo1104 · 10-15-2011, 12:34 PM

dosent n54 have more horse power due to bmw underrating the engine? So isnt n54 quicker than n55? Not to mention it being more mod friendly than n55...

Barbja · 10-16-2011, 08:16 PM

Quote:

Originally Posted by joech

I am the opposite. I have the 50i tip and I love the sound.

I have the square tips installed too and I also like the sound. However, I've had several people ask me if my car was supposed to sound like that. Some more than once! (Like the answer would change?)

Kanuc · 10-26-2011, 09:48 PM

Quote:

Originally Posted by joech

I am the opposite. I have the 50i tip and I love the sound.

+1!!!!!!!!!

zerrantoss · 10-27-2011, 11:11 AM

Quote:

Originally Posted by Kanuc

+1!!!!!!!!!

You already have 50i engine

doug_999 · 11-01-2011, 08:19 PM

clarification for all... N54/N55 are the 35i designation. As noted, getting the 50i (2008-2012) and it is going to sound INCREDIBLE (to be honest, that was one of the MAIN reasons I went with the V8, the SOUND!).

The N55 makes torque a bit lower and the N54 makes a bit more power up top. So around town the N55 should feel faster - especially with the 8 speed.

Here is where the misconception begins.... the 8 speed is not smooth from the start (at least not on the 50i I own and the 35i I test drove). It is hard to come off the line smoothly - either you come off real slow, or crazy fast (I believe it starts out in 2nd but will drop down to 1st if it detects too much throttle). The 6 speed seemed to be a much easier trans from the line (others have posted this as well).

Alas, as noted, the 8 speed gets about 2 more mpg.

zerrantoss · 11-03-2011, 12:20 AM

Quote:

Originally Posted by doug_999

As noted, getting the 50i (2008-2012) and it is going to sound INCREDIBLE (to be honest, that was one of the MAIN reasons I went with the V8, the SOUND!).

50i does have a much deeper sound. I am very jealous!

I guess there is no way for me to get a sound like that without an engine swap

How does N54 sound compare to N55?

solidgold · 11-04-2011, 04:24 AM

Looks like the entire 35i line-up has done the transition from N54 to N55. These include X3 (new though), X5, X6, F10 (new though). Somehow, the Z4 and 335 did not get the new N55 engine. They could have easily done that on the Z4 E89 when they launched the 35is, but they did not. I am not sure why. There are unconfirmed sources that the N54 can produce more low-end torque when properly tuned or have the capacity if tune right. Notice that only the 2-door sports model are still on N54.

AndreyATC · 11-04-2011, 08:38 AM

As far as i remember N54 had almost zero lag and great low end torque in the very beginning of its production
Then BMW started "fixing" wastegate issues by updating ECU software and creating lag that everyone was complaining about
If i had a choice, i'd still pick N54 over 55 for any application
I still think it's a better engine with more potential
And I had pleasure driving it for 4 yrs

P.S. N54 sounds much nicer too

10-13-2011, 08:27 AM	#1
apollner Private 15 Rep 70 Posts Drives: 2009 X6 Join Date: Dec 2008 Location: DC iTrader: (0)	N54 vs N55 and 6sp vs 8sp My lease is wrapping up on my 2009 X6 35i. I really have enjoyed the car so much, I've ordered another one! The current models now use the N55 engine and 8 speed transmission vs. my car's N54 engine and 6 speed. Does anyone have any feedback from back-to-back comparisons on how these two changes affect the X6?
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10-13-2011, 12:16 PM	#2
zerrantoss First Lieutenant 25 Rep 333 Posts Drives: 2011 X6 Join Date: Nov 2010 Location: Vancouver iTrader: (0)	I haven't personally driven a N54 X6, but have heard comments about it. A lot of people are saying 8 spd is a lot smoother than 6 spd - should be true, given that you have 2 more gears.. However, I am not liking the sound of my N55 exhaust (with the right side opened with golf-tee mod, or with performance exhaust installed, etc). It sounds a bit "broken" to me...especially after a cold start. I am not sure if anyone else feel the same way.
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10-13-2011, 12:54 PM	#3
AndreyATC Banned 99 Rep 1,828 Posts Drives: 2016 Tesla Model X P90DL Join Date: Oct 2006 Location: Near NYC iTrader: (2) Garage List 2016 Tesla Model X [0.00] 2015 Tesla Model S ... [9.00]	Besides smothiness, 8-speed equipped car is quicker and has better MPG than 6-speed variant 8AT might be even lighter in weight than 6AT, but i could be wrong
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10-15-2011, 12:34 PM	#5
chocobo1104 New Member 8 Rep 26 Posts Drives: 2011 BMW X6 35i Join Date: Jul 2010 Location: Toronto iTrader: (0)	dosent n54 have more horse power due to bmw underrating the engine? So isnt n54 quicker than n55? Not to mention it being more mod friendly than n55...
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11-01-2011, 08:19 PM	#9
doug_999 Brigadier General 2545 Rep 3,968 Posts Drives: 2011 1M/2021 992/2023 X3 Join Date: Mar 2008 Location: Chicago, IL iTrader: (0)	clarification for all... N54/N55 are the 35i designation. As noted, getting the 50i (2008-2012) and it is going to sound INCREDIBLE (to be honest, that was one of the MAIN reasons I went with the V8, the SOUND!). The N55 makes torque a bit lower and the N54 makes a bit more power up top. So around town the N55 should feel faster - especially with the 8 speed. Here is where the misconception begins.... the 8 speed is not smooth from the start (at least not on the 50i I own and the 35i I test drove). It is hard to come off the line smoothly - either you come off real slow, or crazy fast (I believe it starts out in 2nd but will drop down to 1st if it detects too much throttle). The 6 speed seemed to be a much easier trans from the line (others have posted this as well). Alas, as noted, the 8 speed gets about 2 more mpg. __________________ 2011 1M, Black loaded sans sat radio 2021 911 C4S Gentian Blue, manual 2023 X3 M40i - loaded sans Park Assist
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11-04-2011, 04:24 AM	#11
solidgold Private 10 Rep 82 Posts Drives: Z4 E89 Join Date: Feb 2010 Location: Singapore iTrader: (0)	Looks like the entire 35i line-up has done the transition from N54 to N55. These include X3 (new though), X5, X6, F10 (new though). Somehow, the Z4 and 335 did not get the new N55 engine. They could have easily done that on the Z4 E89 when they launched the 35is, but they did not. I am not sure why. There are unconfirmed sources that the N54 can produce more low-end torque when properly tuned or have the capacity if tune right. Notice that only the 2-door sports model are still on N54.
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11-04-2011, 08:38 AM	#12
AndreyATC Banned 99 Rep 1,828 Posts Drives: 2016 Tesla Model X P90DL Join Date: Oct 2006 Location: Near NYC iTrader: (2) Garage List 2016 Tesla Model X [0.00] 2015 Tesla Model S ... [9.00]	As far as i remember N54 had almost zero lag and great low end torque in the very beginning of its production Then BMW started "fixing" wastegate issues by updating ECU software and creating lag that everyone was complaining about If i had a choice, i'd still pick N54 over 55 for any application I still think it's a better engine with more potential And I had pleasure driving it for 4 yrs P.S. N54 sounds much nicer too Last edited by AndreyATC; 11-04-2011 at 08:44 AM..
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